Use Of Fungicides Research Articles

Targeted Chemical Strategies in Planting Holes: A Proactive Approach to Managing Phytophthora Crown Rot of Strawberry

Phytophthora crown rot (PhCR) of strawberry, most commonly caused by P. cactorum, is introduced in annual cropping systems on quiescently infected transplants. In Florida, preventative chemical treatments are applied through drip tapes promptly after plant establishment. Since strawberry plants are especially vulnerable to PhCR during the establishment period, delaying fungicide treatments can result in stand loss, reduced productivity and suboptimal fungicide efficacy. This project evaluated the effectiveness of applying Ridomil Gold® and Orondis® Gold directly to planting holes prior to transplanting. Results from trials over four growing seasons (2019–2024) demonstrated that fungicides applied in planting holes consistently reduced PhCR incidence and progression as effectively or more than products applied via drip. These findings suggest that direct in-hole fungicide application could be an alternative for managing PhCR in strawberry. These findings warrant further research into dosage and volume optimization, and the development of precision hole-punch applicators. Such technology could lead to more strategic fungicide use by placing the treatment only where needed, i.e. the root zone, and at the crucial timing of planting establishment. It also has the potential to improve disease control outcomes, enhance productivity, and reduce the need for further fungicide applications to control PhCR, thereby decreasing the risk of resistance development to key fungicides.

Utilizing High-Resolution Imaging and Artificial Intelligence for Accurate Leaf Wetness Detection for the Strawberry Advisory System (SAS).

In strawberry cultivation, precise disease management is crucial for maximizing yields and reducing unnecessary fungicide use. Traditional methods for measuring leaf wetness duration (LWD), a critical factor in assessing the risk of fungal diseases such as botrytis fruit rot and anthracnose, have been reliant on sensors with known limitations in accuracy and reliability and difficulties with calibrating. To overcome these limitations, this study introduced an innovative algorithm for leaf wetness detection systems employing high-resolution imaging and deep learning technologies, including convolutional neural networks (CNNs). Implemented at the University of Florida's Plant Science Research and Education Unit (PSREU) in Citra, FL, USA, and expanded to three additional locations across Florida, USA, the system captured and analyzed images of a reference plate to accurately determine the wetness and, consequently, the LWD. The comparison of system outputs with manual observations across diverse environmental conditions demonstrated the enhanced accuracy and reliability of the artificial intelligence-driven approach. By integrating this system into the Strawberry Advisory System (SAS), this study provided an efficient solution to improve disease risk assessment and fungicide application strategies, promising significant economic benefits and sustainability advances in strawberry production.

A Review of Plant Growth Promoting Rhizobacteria and Their Characteristics as Potential Biofertilizer

The growing demand for agricultural products for food requirements caused the use of excessive inorganic chemical fertilisers, insecticides, fungicides, and pesticides for a quick and simple way to maximise and boost crop yield. This practice harmed food safety and caused the degradation of environmental, physical, and biological conditions. It has become alarming, and now is the time for a greener approach to increase agricultural output while minimising the use of inorganic chemical fertilisers. It was proven through many previous studies that using environmentally friendly biofertilisers has managed to increase crop yield while reducing the usage of chemical fertilisers. Plant growth-promoting rhizobacteria (PGPR) are mostly used in biofertiliser production because these types of microbes will enhance plant growth and yield by mobilising the available nutrients through several biological mechanisms, including fixation of atmospheric nitrogen, solubilisation, and mobilisation of phosphate and potassium, phytohormones production, disease suppression, and stress protection. Understanding their characteristics, biological mechanisms of action, and the nutritional and physical requirements for growth is important for successfully formulating and applying PGPR as a biofertiliser. The selection of the right PGPR with the desired characteristics, the ability to adapt to the environment, and the ideal formulation of the biofertiliser are the main criteria that should be emphasised when determining the success of biofertiliser. Knowledge and awareness regarding the use, benefits, and production of PGPR as a potential biofertiliser are important and should be explored to fulfil the crop’s nutritional requirements more economically and sustainably.

Effect of calcium propionate dip and spray applications on botrytis blight of ornamental plants

The use of conventional fungicides to control botrytis blight of ornamentals caused by Botrytis cinerea has its limitations due to increasing resistance to site-specific fungicides. Calcium propionate (CaP) has suppressive action against this disease and resistance in B. cinerea to CaP has not been reported. This study evaluated the efficacy of postharvest dip applications of 0.1% CaP (pH 6.0) to control botrytis blight in four cut rose (Rosa ×hybrida) cultivars and analyzed gene expression of CaP-treated rose petals. CaP reduced botrytis blight symptoms in rose ‘Alive’ but not in ‘Freedom’, ‘Momentum’, and ‘Orange Crush’, and no change in gene expression in ‘Orange Crush’ was detected following CaP treatment. Aerial spray applications at 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% CaP made twice a week for 5 weeks caused minimal phytotoxicity damage to calendula (Calendula officinalis), carnation (Dianthus sp), dahlia (Dahlia sp), pansy (Viola ×wittrockiana), and snapdragon (Antirrhinum majus) leaves; however, CaP spray applications generated residues at all CaP concentrations in all species except for dahlia where no residue was observed. The results suggest that CaP will suppress botrytis blight in some but not all rose cultivars and establish a reference for phytotoxicity symptoms and visible CaP residues on ornamental plants.

Bakanae Disease Resistance in Rice: Current Status and Future Considerations

Bakanae disease is mainly caused by Fusarium fujikuroi and is a significant fungal disease with a number of disastrous consequences. It causes great losses in rice production. However, few studies have focused on the details of bakanae disease resistance in rice. Here, we summarize and discuss the progress of bakanae disease resistance in rice. Besides rice germplasm screening and resistance-related gene/quantitative trait locus (QTL) exploration, the route of pathogen invasion in rice plants was determined. We further discussed the regulation of phytohormone-related genes and changes in endogenous phytohormones in rice plants that are induced by the pathogen. To achieve better control of bakanae disease, the use of natural fungicides was assessed in this review. During rice—F. fujikuroi interactions, the infection processes and spatial distribution of F. fujikuroi in infected seedlings and adult plants exhibit different trends. Fungal growth normally occurs both in resistant and susceptible cultivars, with less abundance in the former. Generally, bakanae disease is seed-borne, and seed disinfection using effective fungicides should always be the first and main option to better control the disease. Besides the friendly and effective measure of using natural fungicides, breeding and utilization of resistant rice cultivars is also an effective control method. To some extent, rice cultivars with low grain quality, indica subspecies, and some dwarf or semi-dwarf rice germplasms are more resistant to bakanae disease. Although no highly resistant germplasms were obtained, 37 QTLs were located, with almost half of the QTLs being located on chromosome 1. Using omics methods, WRKYs and MAPKs were usually found to be regulated during rice—F. fujikuroi interactions. The regulation of certain phytohormone-related genes and changes in some endogenous phytohormones induced by the pathogen were clear, i.e., it downregulated gibberellin-related genes and repressed endogenous gibberellins in resistant genotypes, but the opposite results were noted in susceptible rice genotypes. Overall, exploring resistant germplasms or resistance-related genes/QTLs for the breeding of rice with bakanae disease resistance, expanding research on the complex mechanism of rice—F. fujikuroi interactions, and using cost-effective and eco-friendly innovative control methods against the disease are necessary for present and future bakanae disease management.

Potato Breeding for Late Blight Resistance in Central and East Africa

Potato late blight is a disease of great loss, which can go beyond 75% in Central and Eastern Africa. With this in mind, in order to limit the excessive use of synthetic fungicides, the use of resistant varieties is a better alternative. This study focuses on the synthesis of works already carried out in the improvement of potato resistance to late blight in Central and East Africa in order to have a general overview. For this purpose, 76 documents were consulted, including 67 scientific articles, eight books, and a web page. The literature has shown that the improvement of potato resistance to late blight in these areas is mainly based on conventional methods throughout the breeding scheme. These studies are mainly led by the International Potato Center. This review covers yield losses due to late blight, the biology of Phytophthora infestans, late blight management methods, the genetics of late blight resistance, genetic resources for late blight resistance in Central and East Africa, screening methods and breeding approaches for potato late blight resistance.

Pseudomonas chlororaphis Metabolites Reduce MfCYP51 Expression and Yield Synergistic Efficacy in Mixture with Reduced Rates of Propiconazole Against DMI-Resistant Monilinia fructicola Isolates.

Brown rot caused by Monilinia fructicola is one of the most important diseases affecting peach production in the southeastern United States. Management often involves the use of demethylation inhibitor (DMI) fungicides, but efficacy can be compromised because of overexpression of the MfCYP51 gene encoding the 14α-demethylase of the ergosterol biosynthesis pathway. This study aimed to investigate the influence of the biorational fungicide Howler EVO containing Pseudomonas chlororaphis ASF009 metabolites on the expression of MfCYP51 in M. fructicola and associated synergy with a DMI fungicide for control of DMI-resistant strains. Mycelia from two DMI-sensitive and three DMI-resistant M. fructicola isolates were exposed or not to propiconazole (0.3 μg/ml), Howler (88.1 μg/ml), or the combination propiconazole + Howler for 6 h prior to RNA extraction. Real-time PCR indicated that Howler reduced the constitutive expression of MfCYP51 in DMI-sensitive and two of three DMI-resistant isolates. Propiconazole-induced expression of the DMI target gene was significantly reduced by Howler and by the mixture of Howler plus propiconazole in all isolates. Detached fruit studies on apple revealed that the combination of Howler plus a reduced label rate of Mentor (50 μg/ml propiconazole) was synergistic against brown rot caused by a DMI-resistant isolate in high and low inoculum spore concentration experiments (synergy values of 40.1 and 4.9, respectively). We hypothesize that the synergistic effects against M. fructicola resistant to DMI fungicides based on MfCYP51 gene overexpression can be attributed to reduced 14α demethylase production due to transcription inhibition, which may necessitate fewer DMI fungicide molecules to arrest fungal growth. The use of Howler/DMI mixtures for brown rot control warrants further investigation because such mixtures could potentially allow for reduced DMI fungicide use rates in the field without compromising yield or increased resistance selection.

In vitro Evaluation of Bio Control Agents and Botanicals against Mulberry Root Rot Pathogen Lasiodiplodia theobromae

Mulberry root rot is fast spreading disease caused by L. theobromae. The pathogen can be managed by synthetic fungicides. However, enormous use of synthetic fungicides leads to residual toxicity which affects the growth and development of silkworm. In this context, an attempt was made to use potential bio control agents for the management of this pathogen. Seven fungal and five bacterial bio agents evaluated out of them T. viride (Tv – B2), T. harzianum (Th - 44), B. subtilis (Bs - M) and (Bs - O) proved as best for inhibition of mycelial growth of the pathogen. Out of eleven botanical extracts used, garlic proved best at 15 per cent and 20 per cent and agave at 20 per cent concentration against root rot causing pathogen L. theobromae.

Comparison of Optimal Control Effect from Fungicides and Pseudomonas Fluorescens on Downy Mildew in Corn

Downy mildew is a disease that continues to infect corn crops in Timor Tengah Utara regency, reducing the amount of crop production and making corn farmers suffer losses. Farmers continue to look for ways to control downy mildew. Two treatments are commonly used by farmers, namely spraying Fungicides and Pseudomonas Fluorescens simultaneously in one unit of time, but have not resulted in optimal production. Therefore, this research is important to get a more optimal way to control find downy mildew. In this paper, we determine the optimal model of downy mildew control in corn plants by comparing the use of Fungicides and Pseudomonas Fluorescens. This research begins by forming a dynamic mathematical model consisting of six populations, namely four corn populations (Sh, F , P , Ih) and two populations of infecting fungi (Sv , Iv ). Then they obtained the basic reproduction number (R0) and two equilibrium points, namely the disease-free equilibrium and the disease-endemic equilibrium which has asymptotic stability. Numerical simulation results based on optimal control analysis with the minimum Pontryagin principle show that using fungicides can reduce the number of plants infected with downy mildew. Therefore, control by using fungicides is necessary and recommended increasing the number of downy mildew infected plants.

Studying on Antifungal Activities of Streptomyces Isolated from Soil and Its Biocontrol Potential Against Fusarium of Chili’s Root Rot Disease

Seven Streptomyces strains from chili farm soil, including Strep-1, Strep-2, Strep-4, Strep-5, Strep-6, Strep-8, and Strep-10, were screened for their antifungal activities against Fusarium sp. of chili's root rot disease. The results showed that Streptomyces sp. Strep-4 and Streptomyces sp. Strep-8 performed potential abilities to control the pathogenic Fusarium of which means of antifungal efficacies were 43,88 ± 3,21% and 51,8 ± 2,54%, in turn. Extensive researches on the effects of inoculum factors on antifungal activity of Streptomyces sp. Strep-8 resulted that this strain spontaneously synthesized the antifungal compounds to control Fusarium in the culture condition with pH 7, 40oC of culture temperature, and 7 days of culture time. The results proved that Streptomyces sp. Strep-8 with its thermophilic ability not only provided significant inhibitory activity against pathogenic Fusarium sp. in vitro also promised to be a potential biological control agent to eliminate this fungus on fields. Moreover, using Streptomyces sp. Strep-8 as a biological control agent helps reduce the use of fungicides which contributes to boosting the sustainability of agricultural ecosystems worldwide.

Compatibility study of Trichoderma sp. with Chemical Fungicides Commonly Used by Nepalese Farmers, Under In-Vitro Condition

The excessive use of synthetic fungicides has led to the emergence offungicide-resistant strains of pathogens, raising concerns about human health andenvironmental impact. Trichoderma spp., an endophytic and versatileopportunistic plant symbiont, has recently gained popularity as a biocontrolagent. Integrated use of Trichoderma with compatible fungicides gives betterdisease management and causes less harm to the environment in the long run.This study aimed to evaluate the compatibility of six fungicides commonly used byNepalese farmers at concentrations of 250, 500, and 1000 ppm with Trichodermasp. using the poisoned food technique in-vitro. The experiment was conducted ina completely randomized design with four replications for each treatment, anddata were taken at 24, 36, 48, 60, and 72 hours after incubation. Among thefungicides tested, Mancozeb was compatible at all concentrations from the startand exhibited the highest compatibility at 72 hours, with a growth inhibitionpercent of 0.39%. Metalaxyl+Mancozeb at 250 and 500 ppm, and Copperoxychloride at 250 ppm showed good compatibility. However, Carbendazim,Hexaconazole, and Carbendazim+Mancozeb resulted in 100% growth inhibition ofTrichoderma sp. throughout the experiment. While all treatments significantlyreduced mycelial diameter, Mancozeb and Metalaxyl+Mancozeb showed agradual decrease in growth inhibition percent over time, indicating increasedcompatibility. In contrast, Copper oxychloride demonstrated variable growthinhibition percent over time. So, the fungicides Mancozeb, Metalaxyl+Mancozeband Copper oxychloride at compatible concentrations can be used withTrichoderma sp. in integrated disease management to control soil and seed-bornepathogens.

Evaluation of Garlic Germplasm for Resistance to Leaf Blight Caused by Stemphylium vesicarium

Leaf blight caused by Stemphylium vesicarium is one of the most important fungal diseases of garlic (Allium sativum L.) worldwide, which results in a reduction of quality and yield. The breeding of resistant cultivars is an efficient approach to decrease the use of chemical fungicides and minimize crop losses. In this study, to find the resistant garlic resources against S. vesicarium, we evaluated the resistance degree of 20 garlic germplasms. To do this, garlic seedlings at four-leaf stage were rubbed with nonabsorbent cotton and then inoculated with spore suspension (3.0×105 spores/ml of potato dextrose broth) of S. vesicarium by spray method. Three to seven days after inoculation, the infected leaf area (%) of garlic seedling was measured. ‘Daeseo’ and ‘Namdo’ were included as susceptible and resistant control cultivars, respectively. After 3 to 7 days of incubation, the infected leaf area (%) of garlic seedling was measured. Our results showed that IT245512, IT245528, and IT244068 lines exhibited the highest resistance against S. vesicarium, whereas IT257134 and IT253043 lines were more susceptible than the susceptible cultivar ‘Daeseo’. Based on the results, the resistant genetic resources selected in this study can be used a basic material for resistant garlic breeding system against leaf blight.

Antifungal Activity and Possible Mechanism of Streptomyces nojiriensis 9-13 Against Mycogone sp., Causing Wet Bubble Disease on Agaricus bisporus.

Wet bubble disease (WBD) in Agaricus bisporus caused by Mycogone species imposes a substantial economic loss to mushroom production in China. Currently, fungicide application is the main method to control WBD. However, excessive use of fungicides is challenged by the appearance of resistance and food safety. Therefore, it is necessary to explore safe and efficient strategies to control WBD. Strain 9-13, isolated from the rhizosphere soil of Taxus chinensis, showed strong inhibitory activity against three Mycogone species. According to morphological and biochemical characteristics and multilocus phylogenetic analysis, the strain was identified as Streptomyces nojiriensis. In addition, strain 9-13 extracts significantly inhibited mycelial growth and spore germination of M. perniciosa, M. rosea, and M. xinjiangensis in vitro. Strain 9-13 and its extracts also exhibited broad-spectrum antifungal activities against 12 selected plant pathogenic fungi. Scanning electron microscopic observations showed that the extracts destroyed mycelial structure, inducing mycelia to twist and shrink. Moreover, transmission electron microscopy revealed that the extracts resulted in severe plasmolysis, rupture of the cell membrane, and a decrease in cell inclusions, and the cell wall had a rough and uneven surface. Notably, the extracts obviously reduced disease severity and incidence of WBD by from 83.85 to 87.32% in fruiting bodies and 77.36% in mushroom beds and maintained fruiting time and color on harvested mushrooms. Collectively, these results clearly indicate that S. nojiriensis 9-13 is a promising biocontrol agent to control WBD on A. bisporus.

Efficacy of Fungicides and Plant Extracts against Fusarium oxysporum f. sp. batatas Incitant of Fusarium Wilt of Sweet Potato (Ipomeae batatas L.)

In vitro experiments were conducted to evaluate the effect of some fungicides and some plant extracts against Fusarium oxysporum f. sp. batatas (Fob). The experiments were conducted in the Plant Pathology Laboratory of the Department of Crop Protection, Bayero University Kano. Three fungicides (Mancozeb, Hexaconazole and Metalaxyl + coprous oxide) and sterile distilled water as control were arranged in a completely randomized design. The treatments were repeated five times. Mancozeb as the most promising fungicide against the fungus was used as a check, other treatments include; 25% aqueous neem leaf extract, 50% aqueous neem leaf extract, 25% aqueous garlic bulb extract, 50% aqueous garlic bulb extract, 25% aqueous callotropis leaf extract, 50% callotropis leaf extract and control. The treatments were arranged in a completely randomized design and repeated thrice. Data on radial growth and percent growth inhibition of the fungus were recorded and subjected to analysis of variance using GenStat 17th Edition. Among the fungicides tested against Fob, Mancozeb significantly had the least radial growth (13mm) and inhibited growth of the pathogen by 71.1% compared to the other fungicides. Bioassay on plant extracts revealed least radial growth of the fungus (36.7mm) and highest percent growth inhibition (43.5%) when 50% aqueous neem leaf extract was used. This differed significantly with the use of 25% aqueous neem leaf extract which caused 39.3 mm radial growth of the fungus and inhibited growth by 38.5%. This was followed by 50% and 25% callotropis leaf extract, respectively with lower fungal growth and higher percent growth inhibition compared to aqueous garlic bulb extract at the different concentrations, exhibiting similar effect on the growth of the fungus and its inhibition. Aqueous neem leaf extract (50%) contained higher phytochemicals than the other botanical extracts at the different concentrations. These phytochemicals are responsible for better suppression of Fob. Application of 50% aqueous neem leaf extract could be further evaluated as potential bio-pesticide to supplement the use of fungicide against Fusarium wilt of sweet potato.

Biocontrol of Fusarium head blight in rice using Bacillus velezensis JCK-7158.

Fusarium head blight (FHB) is a destructive disease caused by several species of Fusarium, such as Fusarium graminearum and F. asiaticum. FHB affects cereal crops, including wheat, barley, and rice, worldwide. Fusarium-infected kernels not only cause reduced yields but also cause quality loss by producing mycotoxins, such as trichothecenes and zearalenone, which are toxic to animals and humans. For decades, chemical fungicides have been used to control FHB because of their convenience and high control efficacy. However, the prolonged use of chemical fungicides has caused adverse effects, including the emergence of drug resistance to pathogens and environmental pollution. Biological control is considered one of the most promising alternatives to chemicals and can be used for integrated management of FHB due to the rare possibility of environment pollution and reduced health risks. In this study, Bacillus velezensis JCK-7158 isolated from rice was selected as an ecofriendly alternative to chemical fungicides for the management of FHB. JCK-7158 produced the extracellular enzymes protease, chitinase, gelatinase, and cellulase; the plant growth hormone indole-3-acetic acid; and the 2,3-butanediol precursor acetoin. Moreover, JCK-7158 exhibited broad antagonistic activity against various phytopathogenic fungi and produced iturin A, surfactin, and volatile substances as active antifungal compounds. It also enhanced the expression of PR1, a known induced resistance marker gene, in transgenic Arabidopsis plants expressing β-glucuronidase (GUS) fused with the PR1 promoter. Under greenhouse conditions, treatments with the culture broth and suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution inhibited the development of FHB by 50 and 66%, respectively. In a field experiment, treatment with the suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution effectively controlled the development of FHB with a control value of 55% and reduced the production of the mycotoxin nivalenol by 40%. Interestingly, treatment with JCK-7158 enhanced the expression of plant defense-related genes in salicylic acid, jasmonic acid, ethylene, and reactive oxygen species (ROS) signaling pathways before and after FHB pathogen inoculation. Taken together, our findings support that JCK-7158 has the potential to serve as a new biocontrol agent for the management of FHB.

Biological control of Aspergillus flavus infection and growth promotion of peanut seedlings by Lactiplantibacillus plantarum and Levilactobacillus brevis

BackgroundAspergillus spp. infection might induce negative effects on peanut seeds, including decreased germination rates and suppressed seedling vigor. Furthermore, A. flavus can secret aflatoxin, regarding food safety and human health. The prolonged use of fungicides for treating mold infections has raised concerns regarding the emergence of fungicide-resistant strains, environmental pollution, and adverse effects on human health. The usage of lactic acid bacteria, including Lactiplantibacillus plantarum and Levilactobacillus brevis for the management of plant diseases, has garnered increasing attention in recent years as a viable alternative to chemical-based therapies. This study aimed to investigate the efficacy of LABs in pre-treating peanut seeds as a biological solution against A. flavus infection before cultivation.ResultsLactiplantibacillus plantarum and Levilactobacillus brevis have demonstrated the ability to suppress A. flavus in vitro. In the in vivo investigation, pre-treatment of peanut seeds with cell-free supernatant derived from L. plantarum (LP-CFS) and L. brevis (LB-CFS) significantly reduced A. flavus infection levels. The conidial count decreased from 8.63 log conidia/g in the untreated group to 5.35 log conidia/g with LP-CFS treatment and 4.59 log conidia/g with LB-CFS treatment. Additionally, A. flavus infection reduced the germination rate of peanut seeds to only 20.4% compared to 63.6% in the control group. In comparison, pre-treatment with LP-CFS and LB-CFS increased the germination rate to 75.6% and 76.8%, respectively, and further improved the vigor index in A. flavus-infected peanut seeds.ConclusionThe present findings indicated that bioactive compounds derived from L. plantarum and L. brevis emerge as promising candidates for treating peanut seeds, effectively protecting them against A. flavus infection. Moreover, these compounds facilitate the growth of seedlings, which could be a potential alternative to chemical fungicides, and contribute to sustainable agricultural development.

Fungicides, bio-controllers and resistance inducers affect bioactive compounds and oxidative metabolism in bell pepper plants inoculated with Phytophthora capsici

ABSTRACT The rational use of chemical fungicides in chilli pepper (Capsicum annuum L.) for controlling Phytophthora capsici Leo. should include molecules that promote induced systemic resistance in the plant. The study objective was to assess how the application of fungicides, bio-controllers and resistance inducers affects bioactive compounds production and oxidative metabolism in pepper plants when inoculated with P. capsici zoospores. Statistical analyses show significant differences in total flavonoids, total phenols and salicylic acid concentrations in plants treated with Trichoderma harzianum, Acibenzolar-S-Methyl (ASM) and phosphonic acid. In addition, the application of ASM and Bacillus subtilis showed the highest values of antioxidant capacity. On the other hand, ASM application favoured increases in superoxide dismutase and phenyl ammonium lyase activity with values of 4.42 ± 0.016 (units · min−1 · g−1) and 3.90 ± 0.22 U · g−1, respectively. However, hydrogen peroxide production was similar to that of phosphonic acid treatments. Similarly, plants treated with B. subtilis and Metalaxyl-M showed increases in peroxidase enzyme activity with values ranging from 2.86 ± 0.05 to 4.52 ± 0.02 (μmol · [mg protein]−1 · min−1). Likewise, phosphonic acid-treated plants exhibited high catalase enzyme activity with values ranging from 2.38 ± 0.032 μmol H2O2 · min−1 · g−1 to 4.30 ± 0.024 μmol H2O2 · min−1 · g−1. The complementary use of products with biological and resistance-inducing functions could help to mitigate the environmental impacts that occur due to the use of chemical fungicides for controlling P. capsici on chilli pepper.

Brown patch severity of five tall fescue cultivars as influenced by summer nitrogen rates

Turf-type tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.: TTTF] is a predominant turfgrass species for lawns throughout cool-humid regions, yet brown patch (caused by Rhizoctonia and Rhizoctonia-like species) can cause severe damage during the summer months. Hypothesized strategies to help minimize brown patch severity and decrease fungicide use includes establishing TTTFs with a high level of host resistance and minimizing summer nitrogen (N) applications. A two-year field study was conducted in West Lafayette, IN to determine the influence of late-spring and summer applied N at two application rates among five TTTF cultivars. Urea-N was applied monthly at two rates from April to July, totaling to 73.5 and 245.0 kg N ha−1. Turf performance was determined using visual ratings for turf quality, relative canopy greenness, disease severity (0–100%), and seasonal brown patch as calculated by area under the disease progress curve (AUDPC). Brown patch was generally not affected by N-rate for any cultivar in either study year. While none of the TTTF cultivars had complete brown patch resistance, cultivar differences were observed, with disease severity ranging from 9.8 to 39.0% and 20.0–51.9% in 2021 and 2022, respectively. Selecting a brown patch resistant cultivar reduced seasonal brown patch severity by 61% across study years compared to the most susceptible cultivars. This study demonstrates that summer N applications to TTTF lawns should not be completely avoided to reduce brown patch as previously suggested and emphasizes the importance of host resistance for disease management.

Inhibition mechanism of Rhizoctonia solani by pectin-coated iron metal-organic framework nanoparticles and evidence of an induced defense response in rice

Nanocrop protectants have attracted much attention as sustainable platforms for controlling pests and diseases and improving crop nutrition. Here, we reported the fungicidal activity and disease inhibition potential of pectin-coated metal-iron organic framework nanoparticles (Fe-MOF-PT NPs) against rice stripe blight (RSB). An in vitro bacterial inhibition assay showed that Fe-MOF-PT NPs (80 mg/L) significantly inhibited mycelial growth and nucleus formation. The Fe-MOF-PT NPs adsorbed to the surface of mycelia and induced toxicity by disrupting cell membranes, mitochondria, and DNA. The results of a nontargeted metabolomics analysis showed that the metabolites of amino acids and their metabolites, heterocyclic compounds, fatty acids, and nucleotides and their metabolites were significantly downregulated after treatment with 80 mg/L NPs. The difference in metabolite abundance between the CK and Fe-MOF-PT NPs (80 mg/L) treatment groups was mainly related to nucleotide metabolism, pyrimidine metabolism, purine metabolism, fatty acid metabolism, and amino acid metabolism. The results of the greenhouse experiment showed that Fe-MOF-PT NPs improved rice resistance to R. solani by inhibiting mycelial invasion, enhancing antioxidant enzyme activities, activating the jasmonic acid signaling pathway, and enhancing photosynthesis. These findings indicate the great potential of Fe-MOF-PT NPs as a new RSB disease management strategy and provide new insights into plant fungal disease management.

Antifungal Properties of Streptomyces bacillaris S8 for Biological Control Applications.

Soybean (Glycine max), a crucial global crop, experiences yearly yield reduction due to diseases such as anthracnose (Colletotrichum truncatum) and root rot (Fusarium spp.). The use of fungicides, which have traditionally been employed to control these phytopathogens, is now facing challenges due to the emergence of fungicide-resistant strains. Streptomyces bacillaris S8 strain S8 is previously known to produce valinomycin t through a nonribosomal peptide synthetase (NRPS) pathway. The objective of this study was to evaluate the antifungal activity of S. bacillaris S8 against C. truncatum and Fusarium sp., assessing its efficacy against soybean pathogens. The results indicate that strain S8 effectively controlled both above-ground and underground soybean diseases, using the NRPS and NRPS-related compound, suggesting its potential as a biological control in plant-microbe interactions. These findings underscore the pivotal role of the stain S8 in fostering healthy soybean microbial communities and emphasize the significance of microbiota structure studies in unveiling potent biocontrol agents.